A While or Awhile?

Have you ever wondered about the differences between "a while" and "awhile"? I like Professor Paul Brians' comments: When "awhile" is spelled as a single word, it is an adverb meaning "for a time" ("stay awhile"); but when "while" is the object of a prepositional phrase, like "Lend me your monkey wrench for a while" the "while" must be separated from the "a." (But if the preposition "for" were lacking in this sentence, "awhile" could be used in this way: "Lend me your monkey wrench awhile.")
Merriam-Webster's Collegiate Dictionary* says, "Although considered a solecism by many commentators, awhile, like several other adverbs of time and place, is often used as the object of a preposition (for awhile there is a silence -- Lord Dunsany).
For the word "while," the dictionary says "1 : a period of time especially when short and marked by the occurrence of an action or a condition : TIME 2 : the time and effort used (as in the performance of an action) : TROUBLE (worth your while)"
Thoroughly confused? Sit back and rest for a while!
*By permission. From Merriam-Webster's Collegiate(R) Dictionary at www.m-w.com by Merriam-Webster, Incorporated.